This invention relates to a method and an apparatus of automatic continuous analysis using an analytical implement which effects taking out the implement, dipping it into a sample solution, performing optical measurement, calculation and disposal of the used sample solution, all automatically.
The analytical implement (2) most widely used today in the analysis of blood, urine and the like has a structure such as that shown in FIG. 3, comprising a transparent plastic strip (2A) provided at one end, a number of reagent sections (2B) corresponding to the number of measuring items and a holding section (2C) at the other end. The reagent sections shown in FIG. 3 are small pieces of filter paper impregnated with a reagent which are bonded to the strip with double-faced adhesive tape (2D). Another form of reagent section (2B) is also available which is a reagent coated together with a base material on the strip to form a film.
There are also other types of analytical implements which are provided near the reagent section (2B) with a reference reflector or on the holding section (2C) with a coating layer (2E) for distinguishing the type and fitting face or position of the reagent section (2B). Those types using black adhesive tape are often used to facilitate optical measurement.
These analytical implements were originally used in the "Dip-and-Read" inspection which determines the concentration of a material by comparison of the color of the implement after being dipped in the solution to be examined with the reference color.
At present, the "read" stage is carried out by instrument to effect determination and, in some cases, the processes of optical measurement, calculation, display of concentration, and the discharge of the analytical implement have been automated.
In contrast, the "dip" stage is still done by manual operation. Each analytical implement is taken out, one at a time, from a closed vessel, set to the optical instrument after being dipped in the sample solution, and disposed of after the measurement has been completed, all manually. This can be a big burden on the operator, particularly when the number of specimens is large. In addition, a certain reaction time is inherent which occupies the operator completely during the measuring. In manual operation, furthermore, variations of the dipping time and the time after dipping until the start of measurement becomes inevitable, resulting in measurement errors. Therefore, it is desirable with regard to cost, accuracy and other points, particularly when treating a large number of specimens, to make the measuring completely automatic, including the "dip" stage.
The complete automation including the "dip" stage, however, requires a device that regularly takes out the analytical implement from the vessel or storage, and also requires an analytical implement automatic handling device which dips the analytical implement, which has been taken out of the vessel or storage, in the sample solution and sets it accurately into the optical measurement section. These devices are required to work accurately and are preferably small-sized and inexpensive. Analytical implements mentioned above are stored in a closed vessel containing a desiccant with their holding sections (2C) directed outward and reagent sections (2B) being directed at random. Thus, it is difficult to take them out automatically.